Barrier movement operators are known in the art which respond to access or security codes wirelessly transmitted from hand held or mounted transmitters by controlling the position of a barrier. One common example of such a barrier movement operator is the ubiquitous automatic garage door operator, however other barrier movement operators for controlling doors, shutters, windows and gates are also known.
Some barrier movement operators store representations of one or more authorized access codes which are compared to received access codes to determine whether permission is to be given to control the barrier. During the early days of security code responsive operators, switches were set in both the transmitter and a receiver of the operator to identify the code to be transmitted and the operator code to which the received codes were compared. Product evolution has provided an advantage whereby security codes are learned at the operator by placing the operator in a learn mode and wirelessly transmitting a security code to be learned. The operator, entered the learning mode at the press of a pushbutton and while in the learning mode, received the transmitted security codes and stored them in memory. Such a learning mode was initiated by manually pressing a learn button on a part of the operator and/or by transmitting a predetermined signal from a transmitter already learned by the operator. The learning mode then terminated for example, a predetermined period of time after its initiation. The learning mode would be entered each time the appropriate pushbutton was pressed. When not in the learning mode the operator is in an operate mode in which received wireless access codes activate the operator if they bear a known relationship to codes already learned by the operator.
The use of an automatic learn mode to learn wirelessly transmitted access codes has simplified the use of barrier operators. Since the simplification of learning access codes there has remained a possibility that an unauthorized individual could press the learn button, cause the operator to enter the learn mode and transmit an unauthorized code to the operator where it was learned. Later, the unauthorized individual could return and transmit the unauthorized code to the operator which would respond by controlling the barrier. A need exists for a method and arrangement of controlling a barrier operator which retains the ease of security code learning and which provides resistance to the learning of unauthorized codes.